package ex107;

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        System.out.print("输入项数: ");
        int n = scanner.nextInt();

        if (n <= 0) {
            System.out.println("不正确的输入");
        } else {
            Util util = new Util();
            System.out.printf("%.8f\n", util.getE(n));
        }
    }
}
